JP4059460B2 - Electric power steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric power steering apparatus equipped in a four-wheel automobile or the like.
[0002]
[Prior art]
FIG. 6 shows a four-wheeled vehicle 2 equipped with a conventional electric power steering device 1. In this electric power steering apparatus 1, an electric motor (DC motor) 5 and a speed reducer 6 are respectively assembled at the lower end portion of a steering column 4 surrounding the steering shaft 3 and disposed on the vehicle body side. The electric motor 5 is rotationally driven based on detection signals from the vehicle speed sensor 7 and the steering sensor 8 disposed on the steering shaft 3, and the steering operation of the steering handle 9 is assisted (assisted) in response to this. It has become. That is, the magnitude of the auxiliary operation force is determined by the controller 10 based on the detection signals output from the vehicle speed sensor 7 and the steering sensor 8, and the operation of the electric motor 5 is controlled by the control signal output from the controller 10. Thus, an appropriate auxiliary operation force is applied to the steering shaft 3. The turning operation force of the steering shaft 3 is transmitted to a steering gear (not shown) in the steering gear box 12 via the transmission shaft 11 so that the front wheels 13a and 13b of the four-wheeled vehicle 2 are steered. It has become.
[0003]
By the way, in the above-described case, the controller 10 is attached to the vehicle body. However, separately from this, the controller (ECU; electronic control unit) 10 for controlling the electric motor is combined with the electric motor 5 of the steering column 4. There has been proposed an electric power steering device that is attached to the lower end portion 4a (see Japanese Patent Laid- Open No. Hei 8-1644861). In the conventional electric power steering apparatus in which the controller 10 is integrated with the steering column 4 as described above, the gear case of the speed reducer 6 attached to the lower end portion 4a of the steering column 4 as shown in FIG. The controller 10 is attached to the upper surface α side of 6a, or, as shown in FIG. 8, the controller 10 is attached to the lower surface β of the gear case 6a.
[0004]
[Problems to be solved by the invention]
However, the conventional electric power steering apparatus in which the controller 10 is integrated with the lower end portion 4a of the steering column 4 as described above has the following problems. That is, when the controller 10 is arranged on the upper surface α of the gear case 6a integrated with the lower end portion 4a of the steering column 4 as shown in FIG. Although necessary, since there is a pedal bracket disposition area in that portion, there is a possibility of causing interference between the controller 10 and a pedal bracket (not shown). Further, since the controller 10 is disposed at a position close to the pedal bracket, there is a problem that maintenance work of the controller 10 cannot be easily performed. On the other hand, when the controller 10 is arranged on the lower surface β of the gear case 6a as shown in FIG. 8, the arrangement position of the controller 10 is at the lower end portion 4a of the steering column 4 and directly below the gear case 6a. Since there is a brake pedal operation area in the portion, there is a possibility that interference occurs between the controller 10 and a brake pedal (not shown).
[0005]
The present invention has been made in view of such problems, and the object of the present invention is to enable the controller to be attached to the steering column at a position outside the pedal bracket interference area or the brake pedal operation area. Interference between the brake pedal and the controller can be prevented, the maintenance work of the controller can be simplified, and a sufficient shock absorbing stroke can be applied to the steering column. Another object is to provide an electric power steering apparatus that can prevent the heat from being attached to the controller and effectively radiate the heat generated by the controller.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, in the present invention, the gear case of the reduction gear disposed at the lower end portion of the steering shaft for transmitting the rotational operation force of the steering handle to the steering gear via the steering shaft, An electric power steering apparatus having a controller for controlling the operation of an electric motor for applying an auxiliary operation force to a steering shaft, wherein the lower part of the gear case is opposed to a steering column surrounding the steering shaft with a space therebetween An overhang extending from the steering wheel toward the steering handle is provided at the lower part of the gear case, the controller is disposed on the lower surface of the overhang, and the overhang is disposed in an inclined state in the vehicle width direction. And the over So that the ribs protruding upward on the upper surface of the lower edge portion of the inclined direction of the ring portion.
In the present invention, the overhang portion is configured as a substantially flat flat plate portion, and the controller is mounted within the range of the lower surface of the overhang portion.
Also, in the present invention, the ribs as well as arranged so as to extend substantially along the vehicle longitudinal direction, continuously from the rear end face of the a root portion of the overhanging portion the gear case to the extended end of the overhang portion It is arranged to extend.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In FIG. 1 to FIG. 5, the same parts as those in FIG. 6 to FIG.
[0008]
FIG. 1 shows a four-wheeled vehicle 2 provided with an electric power steering apparatus 20 according to an embodiment of the present invention. In FIG. 1, reference numeral 21 denotes an arrangement range of the steering column 4 which is disposed so as to surround the steering shaft 3 and is attached to the vehicle body via brackets 22a, 22b and the like. In addition, an electric motor 5 for applying an auxiliary operation force is integrally attached in a state of crossing the axis of the steering column 4. Further, a gear case 6a (a member indicated by cross-hatching R in FIG. 2) of the speed reducer 6 is integrally attached to the lower end portion 4a of the steering column 4, and a controller (for controlling the electric motor) (below the gear case 6a). ECU) 10 is attached in the following state.
[0009]
That is, as clearly shown in FIG. 2 and FIG. 4, at the end of the gear case 6 a of the reduction gear 6 on the lower surface side and the vehicle rear side (side near the steering handle 9), on the outer peripheral surface 4 b of the steering column 4. On the other hand, an overhang portion 23 extending from the lower portion of the gear case 6a toward the side closer to the steering handle 9 is provided so as to face in parallel with a slight gap (gap S shown in FIGS. 2 and 3). The controller 10 is disposed on the lower surface 23 a of the overhang portion 23. The above-described overhang portion 23 is configured as a substantially flat flat plate portion, and is formed to have a size slightly larger than the size (projected area) of the controller 10, and the overhang portion is formed of this flat flat plate portion. The controller 10 is fixed by bolting or the like in a state in which the entire mounting surface is disposed within the range of the lower surface 23a of 23. Thus, the electric motor 5 is rotationally driven by the control signal output from the controller 10 in accordance with the vehicle speed signal, the rotation information signal of the steering shaft 3, and the like, whereby an auxiliary operation force is appropriately applied to the steering shaft 3, and this The rotational operation force of the steering shaft 3 is transmitted to the transmission shaft 11 and a steering gear (not shown) in the steering gear box 12 so that the front wheels 13a and 13b are steered (see FIG. 1).
[0010]
Further, as shown in FIG. 4, the controller 10 is disposed at a position where the brake pedal 24 is moved backward with respect to the brake pedal 24 disposed on the side of the steering column 4 (position when not braked). Rather than the rear side of the vehicle body. As shown in FIGS. 2, 4, and 5, the clearance S between the overhang portion 23 of the gear case 6 a and the steering column 4 facing the overhang portion 23 is an outer peripheral surface 4 b of the steering column 4. Further, it is provided as a so-called “escape portion” in which a step portion 4d between the column portion 4c and the outer peripheral surface 4b which is a rear portion of the vehicle body and slightly larger in diameter can enter.
[0011]
Further, in the present embodiment, the overhang portion 23 composed of a substantially flat flat plate portion is inclined with respect to the horizontal plane H as shown in FIG. 3, that is, in an inclined state in the vehicle width direction (for example, a downward sloping inclination in FIG. 3). A rib 25 for reinforcing and water guiding projecting upward is integrally formed on the upper surface of the lower end edge portion 23b in the inclined direction of the overhang portion 23. Yes. The rib 25 is disposed so as to extend substantially along the vehicle longitudinal direction, and continuously extends from the rear end surface of the gear case 6a, which is the base portion of the overhang portion 23, to the extending end of the overhang portion 23. It is arranged like this. Specifically, the linear top portion P (see FIG. 2) of the rib 25 is disposed at a position close to the outer peripheral surface 4 b of the steering column 4.
[0012]
According to the electric power steering apparatus 20 having such a configuration, the controller 10 is arranged at the lower part (location on the lower surface side) of the gear case 6a, so that the controller 10 interferes with a pedal bracket (not shown). In addition, since the controller 10 is mounted on the overhang 23 that extends from the main body of the gear case 6a toward the steering handle 9, the controller 10 is disposed at a position outside the brake pedal operating area. be able to. Therefore, it is possible to eliminate a problem that causes interference between the controller 10 and the pedal bracket and the brake pedal. Moreover, when performing maintenance such as replacement of the controller 10, maintenance work can be performed without removing the steering column 4, so that maintenance workability can be improved.
[0013]
Further, since the clearance S is provided as an escape portion between the overhang portion 23, which is the mounting portion of the controller 10, and the outer peripheral surface 4b of the steering column 4, an excessive impact force is applied to the steering system, and the steering column. When 4 is contracted and deformed as shown in FIG. 5, the stepped portion 4 d of the steering column 4 can be contracted and deformed while entering the gap (escape portion) S. Therefore, a sufficiently large contraction stroke of the steering column 4 can be secured, and as a result, the impact force can be sufficiently absorbed by the contraction deformation of the steering column 4. When the electric motor 5 is arranged above the steering column 4, a sufficient shock absorbing stroke can be ensured by the interference between the bracket 22 a for mounting the steering column 4 on the vehicle body and the electric motor 5. In addition, there is a risk that the electric motor 5 is at the upper side, which may cause a harmful effect of vibration. However, according to the present embodiment, a sufficient shock absorbing stroke can be ensured as described above, and there is also a problem of vibration. It does not occur.
[0014]
Furthermore, the structure of the electric power steering apparatus 20 of the present embodiment is effective in preventing the water or the like from touching the controller 10 when water or the like adheres to the steering column 4 and flows along the outer peripheral surface thereof. Structure. For example, when the occupant gets into the passenger compartment with clothes wet with rainwater, the rainwater adheres to the steering column 4 and flows along the outer peripheral surface, or even if rainwater scatters on the steering column 4, the controller 10 Since the overhang portion 23 having a large size (area) serves as a water avoidance member, it is possible to prevent the rainwater (water droplets) from touching the controller 10 due to the presence of the overhang portion 23. In addition, the rainwater flowing along the steering column 4 flows along the upper surface of the inclined overhang portion 23 to the lower side of the inclination, is dammed by the rib 25, and is guided to the front end side of the controller. The water will be discharged without touching 10. Therefore, the malfunction of the controller 10 due to the adhesion of water to the controller 10 can be avoided in advance. In addition, the above-mentioned rib 25 fulfill | performs not only the water guidance function as stated above but the reinforcement function of the overhang part 23 in which this controller 10 is mounted. Further , since the rib is provided in the overhang portion integrally formed with the gear case, the presence of the rib increases the heat radiating surface area, so that the heat generated by the controller can be effectively radiated.
[0015]
Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. For example, if the position where the overhang portion 23 is provided in the gear case 6a is the lower rear end portion of the vehicle body, the position in the vehicle width direction may be selected so as not to interfere with the brake pedal operating region.
[0016]
【The invention's effect】
According to the first aspect of the present invention, an overhang portion extending from the lower portion of the gear case toward the steering handle is provided at the lower portion of the gear case so as to face the steering column surrounding the steering shaft with a space therebetween. The controller is disposed (mounted) on the lower surface of the overhang portion, the overhang portion is disposed in an inclined state in the vehicle width direction, and the upper side of the lower edge portion of the overhang portion is inclined upward. Because the projecting rib is provided , the controller interferes with peripheral parts such as the brake pedal and pedal bracket as the controller is mounted overhanging the steering column at the bottom of the gear case. It becomes possible to arrange so that it does not occur. In addition, since the controller is mounted on the overhang portion, it is possible to easily perform operations such as replacement and inspection of the controller without removing the steering column from the vehicle body during maintenance work. Furthermore, by mounting the controller overhanging as described above, the clearance between the overhang portion and the steering column in the overhang portion absorbs the shrinkage deformation of the steering column during the impact action. And a sufficient shock absorbing stroke can be secured. In addition, the overhang portion is disposed in an inclined state in the vehicle width direction, and a rib projecting from the overhang portion toward the steering column is provided on the upper surface of the lower edge portion of the overhang portion in the inclination direction. Therefore, it is possible to receive the water flowing through the steering column at the overhanging part in the inclined state and block it with the ribs, so that the controller will not be damaged by water. be able to. Further, since the rib is provided in the overhang portion integrally formed with the gear case, the presence of the rib can reinforce the overhang portion, and a large surface area for dissipating the heat generated by the controller. Can be effectively dissipated.
[0017]
According to the second aspect of the present invention, the overhang portion is configured as a substantially flat flat plate portion, and the controller is attached within the range of the lower surface of the overhang portion. Even if a situation occurs such that it adheres and flows along this, the overhang part that is placed so as to cover the entire range of the upper part of the controller serves as a water avoidance, and water etc. touches the controller Occurrence of a situation that causes a malfunction can be prevented.
[0019]
According to a third aspect of the present invention, the ribs are arranged so as to extend substantially along the vehicle longitudinal direction, and are continuous from the rear end surface of the gear case, which is the base portion of the overhang portion, to the extended end of the overhang portion. Therefore, it is possible to reliably discharge water from a location where the controller does not touch the controller due to the presence of the rib.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a four-wheeled vehicle 2 provided with an electric power steering apparatus according to an embodiment of the present invention.
FIG. 2 is a side view showing a configuration of an electric power steering apparatus according to an embodiment of the present invention.
FIG. 3 is an enlarged cross-sectional view taken along line AA in FIG.
FIG. 4 is a side view showing an arrangement state of the electric power steering apparatus according to the embodiment of the present invention.
FIG. 5 is a side view showing a deformed state of the electric power steering apparatus during an impact action.
FIG. 6 is a side view schematically showing a four-wheeled vehicle 2 provided with a conventional electric power steering device.
FIG. 7 is a side view showing an example of an arrangement position of a controller in a conventional electric power steering apparatus.
FIG. 8 is a side view showing another example of the position of the controller in the conventional electric power steering apparatus.
[Explanation of symbols]
2 Four-wheeled vehicle 3 Steering shaft 4 Steering column 4a Lower end portion 4b Outer peripheral surface 4c Large-diameter column portion 4d Stepped portion 5 Electric motor (DC motor)
6 Reducer 6a Gear case
DESCRIPTION OF SYMBOLS 10 Controller 20 Electric power steering apparatus 23 Overhang part 23a Lower surface 23b Lower edge part 24 Brake pedal 25 Rib S Clearance (escape part)

Claims (3)

Actuates an electric motor that applies auxiliary operating force to the steering shaft in the gear case of the reduction gear disposed at the lower end of the steering shaft to transmit the rotational operating force of the steering handle to the steering gear via the steering shaft In the electric power steering apparatus to which a controller to be controlled is attached, an overhang extending from a lower portion of the gear case toward the steering handle so as to face the steering column surrounding the steering shaft with a space therebetween. A hang portion is provided at a lower portion of the gear case, the controller is disposed on a lower surface of the overhang portion, the overhang portion is disposed in an inclined state in a vehicle width direction, and the lower direction of the overhang portion is inclined. On top of side edge Electric power steering apparatus characterized by a rib which projects towards.   2. The electric power steering apparatus according to claim 1, wherein the overhang portion is configured as a substantially flat flat plate portion, and the controller is attached within a range of a lower surface of the overhang portion. The rib is disposed so as to extend substantially along the vehicle longitudinal direction, and is disposed so as to continuously extend from a rear end surface of the gear case, which is a base portion of the overhang portion, to an extending end of the overhang portion. The electric power steering apparatus according to claim 1 , wherein the electric power steering apparatus is an electric power steering apparatus.

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